Semiconductor device, semiconductor module and hard disk

ABSTRACT

The back surface of a semiconductor chip ( 16 ) is exposed from the back surface of an insulating resin ( 13 ), and a metal plate ( 23 ) is affixed to this semiconductor chip ( 16 ). The back surface of this metal plate ( 23 ) and the back surface of a first supporting member ( 11 ) are substantially within a same plane, so that it is readily affixed to a second supporting member ( 24 ). Accordingly, the heat generated by the semiconductor chip can be efficiently dissipated via the metal plate ( 23 ) and the second supporting member ( 24 ).

BACKGROUND OF THE INVENTION

The present invention relates to a semiconductor device, a semiconductormodule and a hard disk, and especially to a structure capable ofefficiently dissipating heat from a semiconductor chip.

Due to the recent growth of the use of semiconductor devices in portabledevices and small/densely-mounted devices, the reduction in size andweight and the improvement in heat dissipation properties are demandedat the same time. In addition, semiconductor devices are mounted onvarious types of substrates, which, in turn, are mounted in various manysystems as semiconductor modules. As for such a substrate, the use of aceramic substrate, a printed board, a flexible sheet, a metal substrateor a glass substrate etc. may be contemplated, and the followingdescription gives one example thereof. Here, the semiconductor module isexplained as being mounted on a flexible sheet.

FIG. 14 shows an example in which a semiconductor module using aflexible sheet is mounted in a hard disk 100. This hard disk may be, forexample, the one described in detail in an article of Nikkei Electronics(No. 691, Jun. 16, 1997, p. 92-).

This hard disk is accommodated within a casing made of a metal, andcomprises a plurality of recording disks that are integrally attached toa spindle motor. Over the surfaces of individual recording disks,magnetic heads are respectively disposed each with a very smallclearance. These magnetic heads are attached at the tips of suspensionswhich are affixed to the ends of respective arms. A magnetic head, asuspension and an arm together form one integral body and this integralbody is attached to an actuator.

The magnetic heads must be electrically connected with a read/writeamplifying IC in order to perform read and write operations.Accordingly, a semiconductor module comprising this read/writeamplifying IC mounted on a flexible sheet is used, and the wiringsprovided on this flexible sheet are electrically connected, ultimately,to the magnetic heads. This semiconductor module is called “flexiblecircuit assembly”, typically abbreviated as “FCA.”

From the back surface of the casing, connectors provided on thesemiconductor module are exposed, and these connector (male or female)and connectors (female or male) attached on a main board are engaged. Onthis main board, wirings are provided, and driving ICs for the spindlemotor, a buffer memory and other ICs for a driving, such as ASIC, aremounted.

The recording disk spins at, for example, 4500 rpm via the spindlemotor, and the actuator detects the position of the magnetic head. Sincethis spinning mechanism is enclosed by a cover provided over the casing,there is no way to completely prevent the accumulation of heat,resulting in the temperature rise in the read/write amplifying IC.Therefore, the read/write amplifying IC is attached to the actuator orthe casing etc. at a location having a better heat dissipation propertythan elsewhere. Further, since revolutions of the spindle motor tend tohigh-speed such as 5400, 7200 and 10000 rpm, this heat dissipation hasmore importance.

In order to provide further detail of the FCA explained above, thestructure thereof is shown in FIGS. 15A and 15B. FIG. 15A is the planview, and FIG. 15B is a cross-sectional view taken along the line A—Awhich cuts across a read/write amplifying IC 115 provided on one end ofthe module. This FCA 117 is attached to an internal portion of thecasing in a folded-state, so that it employs a first flexible sheet 116have a two-dimensional shape that can easily be folded.

On the left end of this FCA 117, the connectors 111 are attached,forming a first connection section 120. First wirings 121 electricallyconnected to these connectors 111 are adhered on the first flexiblesheet 116, and they extend all the way to the right end. The firstwirings 121 are then electrically connected to the read/write amplifyingIC 115. Leads 122 of the read/write amplifying IC 115 to be connected tothe magnetic heads are connected with second wirings 123 which, in turn,are electrically connected to third wirings 126 on a second flexiblesheet 124 provided over the arm and suspension. That is, the right endof the first flexible sheet 116 forms a second connection section 127 atwhich the first flexible sheet 116 is connected to the second flexiblesheet 124. Alternatively, the first flexible sheet 116 and the secondflexible sheet 124 may be integrally formed. In this case, the secondwirings 123 and the third wirings 126 are provided integrally.

On the back surface of the first flexible sheet 116 on which theread/write amplifying IC 115 is to be provided, a supporting member 128is disposed. As for this supporting member 128, a ceramic substrate oran Al substrate may be used. The read/write amplifying IC 115 isthermally coupled with a metal that is exposed to inside of the casingthrough this supporting member 128, so that the heat generated in theread/write amplifying IC 115 can be externally released.

With reference to FIG. 15B, a connecting structure between theread/write amplifying IC 115 and the first flexible sheet 116 will nowbe explained.

This flexible sheet 115 is constituted by laminating, from the bottom, afirst polyimide sheet 130 (first PI sheet), a first adhesion layer 131,a conductive pattern 132, a second adhesion layer 133 and a secondpolyimide sheet 134 (second PI sheet), so that the conductive pattern132 is sandwiched between the first and second PI sheets 130 and 134.

In order to connect the read/write amplifying IC 115, a portion of thesecond PI sheet 134 and the second adhesion layer 133 are eliminated ata desired location to form an opening 135 which exposes the conductivepattern 132. The read/write amplifying IC 115 is electrically connectedthereto through leads 122 as shown in the figure.

The semiconductor device packaged by an insulating resin 136 as shown inFIG. 15B has heat dissipating paths indicated by arrows for externallydissipating its heat, but there has been a problem in that, due to thethermal resistance given by the insulating resin 136, the heat generatedby the read/write amplifying IC 115 cannot be efficiently dissipated tothe outside the device.

Further details will now be explained using this example in hard diskapplication. As for the read/write transfer rate of a hard disk, afrequency of 500 MHz to 1 GHz, or even a greater frequency, is required,so that the read/write speed of the read/write amplifying IC 115 must befast. To this end, the paths of the wirings on the flexible sheet thatare connected to the read/write amplifying IC 115 has to be reduced, andthe temperature rise in the read/write amplifying IC 115 must besuppressed.

Especially, since the recording disks are spinning at a high speed, andthe casing and the lid provide a sealed space, the interior temperaturewould rise up to around 70 to 80° C. On the other hand, a typicalallowable temperature for the operation of an IC is approximately 125°C. This means that, from the interior temperature of 80° C., a furthertemperature rise by approximately 45° C. is permissible for theread/write amplifying IC 115. However, where the thermal resistance ofthe semiconductor device itself and FCA is large, this allowableoperation temperature can easily be exceeded, thereby disabling thedevice to provide its actual performance level. Accordingly, asemiconductor device and FCA having superior heat dissipating propertiesare being demanded.

Furthermore, since the operation frequency is expected to furtherincrease in the future, further temperature rise is also expected in theread/write amplifying IC 115 itself due to the heat generated bycomputing operations. At room temperature, the IC can provide theperformance at its intended operation frequency, however, where it isplaced inside of a hard disk, its operation frequency has to be reducedin order to restrain the temperature rise.

As described above, further heat dissipating properties of semiconductordevice, semiconductor module (FCA) are demanded in connection with theincrease of the operation frequency in the future.

On the other hand, the actuator, and the arms, suspensions and magneticheads attached thereto has to be designed as light-weighted as possiblein order to reduce the moment of inertia. Especially, where theread/write amplifying IC 115 is mounted on the surface of the actuator,the weight reduction is demanded also for the IC 115 and FCA 117.

SUMMARY OF THE INVENTION

The present invention was invented in consideration with the aboveproblems, and in the first aspect, it provides a semiconductor devicecomprising a semiconductor chip integrally sealed by an insulatingresin, the back surfaces of the semiconductor chip and a metal memberhaving a pad electrically connected to a bonding electrode of thesemiconductor chip, being exposed from the back surface of thesemiconductor device, wherein the problem is solved by providing a metalplate on the exposed portion of the semiconductor chip in a manner sothat the metal plate protrudes beyond the back surface of the metalmember.

Since this protrusive metal plate would become within a same plane withthe back surface of the flexible sheet which is the first supportingmember, the structure allows the metal plate to be adhered or abutted toa heat-dissipating plate which is the second supporting member.Accordingly, the heat from the semiconductor chip can be transmitted tothe heat-dissipating plate.

In the second aspect, the problem is solved by disposing the backsurface of the metal member and the back surface of the semiconductorchip substantially within a same plane.

In the third aspect, the problem is solved by using the insulating resinto affix the semiconductor chip.

In the fourth aspect, the problem is solved by affixing the back surfaceof the semiconductor chip and the metal plate together using aninsulating material or a conductive material.

In the fifth aspect, the problem is solved by having the back surface ofthe insulating resin protrude beyond the back surface of the metalmember.

In the sixth aspect, the problem is solved by having the side surfacesof the metal member and the back surface of the insulating resin thatextends from the side surfaces of the metal member define a same curvedsurface.

In the seventh aspect, a semiconductor module is provided, whichcomprises a first supporting member having a conductive pattern providedtherein and a semiconductor device comprising a semiconductor chip whichis electrically connected to the conductive pattern and is integrallysealed by an insulating resin, the back surfaces of the semiconductorchip and a metal member having a pad electrically connected to a bondingelectrode of the semiconductor chip being exposed from the back surfaceof the semiconductor device, wherein the problem is solved byelectrically connecting the metal member to the conductive patternprovided in the first supporting member, and providing an opening to thefirst supporting member at a location which corresponds to thesemiconductor chip, the opening accommodating a metal plate which isaffixed to the back surface of the semiconductor chip.

In the eighth aspect, the problem is solved by adhering a secondsupporting member having the metal plate affixed thereto to the backsurface of the first supporting member.

In the ninth aspect, the problem is solved by providing a fixation platemade of a conductive material over the second supporting member at alocation which corresponds to the metal plate, and by thermally couplingthe fixation plate and the metal plate.

In the tenth aspect, the problem is solved by forming, respectively, themetal plate mainly by Cu, the second supporting member mainly by Al, andthe fixation plate by a plated film mainly made of Cu formed on thesecond supporting member.

In the eleventh aspect, the problem is solved by having the back surfaceof the insulating resin protrude beyond the back surface of the metalmember.

In the twelfth aspect, the problem is solved by having the side surfacesof the metal member and the back surface of the insulating resin whichextends from the side surfaces of the metal member define a same curvedsurface.

In the thirteenth aspect, the problem is solved by using thesemiconductor chip as a read/write amplifying IC for a hard disk.

In the fourteenth aspect, a semiconductor device is provided, whichcomprises a semiconductor chip integrally sealed by an insulating resin,the back surfaces of the semiconductor chip, a metal member having a padelectrically connected to a bonding electrode of the semiconductor chipand an external connection electrode that extends via a wiring integralwith the metal member being exposed from the back surface of thesemiconductor device, wherein the problem is solved by disposing a metalplate over the back surface of the semiconductor chip in a manner so asthat the metal plate protrudes beyond the back surface of the externalconnection electrode.

In the fifteenth aspect, the problem is solved by disposing the backsurface of the external connection electrode and the back surface of thesemiconductor chip substantially within a same plane.

In the sixteenth aspect, the problem is solved by affixing the backsurface of the semiconductor chip and the metal plate together by aninsulating material or a conductive material.

In the seventeenth aspect, the problem is solved by having the backsurface of the insulating resin protrude beyond the back surface of theexternal connection electrode.

In the eighteenth aspect, the problem is solved by having the sidesurfaces of the external connection electrode and the back surface ofthe insulating resin extending from the side surfaces of the externalconnection electrode define a same curved surface.

In the nineteenth aspect, a semiconductor module is provided, whichcomprises a first supporting member having a conductive pattern providedtherein and a semiconductor device comprising a semiconductor chip whichis electrically connected to the conductive pattern and is integrallysealed by an insulating resin, the back surfaces of the semiconductorchip, a metal member having a pad electrically connected to a bondingelectrode of the semiconductor chip and an external connection electrodeprovided via a wiring which is integral with the metal member beingexposed from the back surface of the semiconductor device, wherein theproblem is solved by electrically connecting the conductive patternprovided in the first supporting member to the external connectionelectrode, and providing an opening in the first supporting member at alocation corresponding to the semiconductor chip, the openingaccommodating a metal plate affixed to the back surface of thesemiconductor chip.

In the twentieth aspect, the problem is solved by adhering a secondsupporting member having the metal plate affixed thereto to the backsurface of the first supporting member.

In the twenty-first aspect, the problem is solved by forming theexternal connection electrode and the metal plate integrally from a samematerial.

In the twenty-second aspect, the problem is solved by providing afixation plate made of a conductive material to the second supportingmember at a location corresponding to the metal plate, and by thermallycoupling the fixation plate and the metal plate.

In the twenty-third aspect, the problem is solved by forming,respectively, the metal plate mainly by Cu, the second supporting membermainly by Al and the fixation plate by a plated film mainly made of Cuformed on the second supporting member.

In the twenty-fourth aspect, the problem is solved by having the backsurface of the insulating adhesive means protrude beyond the backsurface of the external connection electrode.

In the twenty-fifth aspect, the problem is solved by having the sidesurfaces of the external connection electrode and the back surface ofthe insulating adhesive means extending from the external connectionelectrode define a same curved surface.

In the twenty-sixth aspect, the problem is solved by using thesemiconductor chip as a read/write amplifying IC for a hard disk.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are diagrams illustrating a semiconductor moduleaccording to the present invention.

FIGS. 2A and 2B are diagrams illustrating a semiconductor deviceaccording to the present invention.

FIGS. 3A and 3B are diagrams illustrating a semiconductor deviceaccording to the present invention.

FIG. 4 is a diagram illustrating a manufacturing step of a semiconductordevice according to the present invention.

FIG. 5 is a diagram illustrating a manufacturing step of a semiconductordevice according to the present invention.

FIG. 6 is a diagram illustrating a manufacturing step of a semiconductordevice according to the present invention.

FIG. 7 is a diagram illustrating a manufacturing step of a semiconductordevice according to the present invention.

FIG. 8 is a diagram illustrating a manufacturing step of a semiconductordevice according to the present invention.

FIG. 9 is a diagram illustrating a semiconductor module of the presentinvention.

FIG. 10 is a diagram illustrating a manufacturing step of asemiconductor device according to the present invention.

FIG. 11 is a diagram illustrating a manufacturing step of asemiconductor device according to the present invention.

FIG. 12 is a diagram illustrating a manufacturing step of asemiconductor device according to the present invention.

FIGS. 13A and 13B are diagrams illustrating a semiconductor deviceaccording to the present invention.

FIG. 14 is a diagram illustrating a hard disk.

FIGS. 15A and 15B are diagrams illustrating a conventional artsemiconductor module.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a thin and small semiconductor devicehaving a superior heat-dissipating capability, and a semiconductormodule having this semiconductor device mounted, such as a semiconductormodule mounted on a flexible sheet (hereinafter referred to as “FCA”),thereby improving the characteristics of, for example, a hard disk.

First, reference shall be made to FIG. 14 illustrating an exemplary harddisk 100 in which an FCA 50 is implemented, and then to FIG. 1A showingthe FCA 50. A semiconductor device mounted on this FCA 50 and themanufacturing method thereof are shown in FIGS. 2 through 13.

Embodiment 1

The first embodiment is provided to illustrate an apparatus in which theFCA 50 is implemented. As for this apparatus, the exemplary hard disk100 that has been used for illustrating the conventional art will beused again.

The hard disk 100 may be mounted on a main board 112 as necessary inorder to place it in a computer etc. This main board 112 includes female(or male) connectors. Male (or female) connectors 111 provided on theFCA 50 and exposed from the back surface of the casing 101 are connectedwith these connectors on the main board 112. Within the casing 101, aplurality of recording disks 102 used as a recording medium are providedin a number corresponding to the storage capacity of the hard disk.Since each of the magnetic heads 104 floats and scans over each of therecording disks 102 at a position approximately 20 nm to 30 nm away fromthe disk, the interval between the recording disks 102 are designed soas to allow this scanning to be undisturbed. The disks are retained atthis interval and attached to a spindle motor 103. This spindle motor103 is mounted on a mounting board, and a connector arranged on the backsurface of this mounting board is exposed from the back surface of thecasing 101. This connector is connected to a connector of the mainboard. Accordingly, mounted on this main board 112 are, a read/writeamplifying IC, an IC for driving the read/write amplifying IC formagnetic heads 104 to which a suspension 106 is connected, an IC fordriving the spindle motor 103, an IC for driving an actuator, a buffermemory for temporarily storing data, and other ASICs etc. forimplementing the manufacturer's own driving scheme. Of course, anyadditional active and passive elements may also be mounted.

The wirings connecting between the magnetic heads 104 and the read/writeamplifying IC are designed to be as short as possible, so that theread/write amplifying IC is disposed on the actuator 107. Since asemiconductor device 10A of the present invention is extremely thin, itmay be attached to the actuator 107 or instead be mounted on the arm105. As shown in FIG. 1B, the back surface of the semiconductor device10A is exposed from the opening 12 of the first supporting member 11 andthermally coupled to the arm 105, so that the heat from thesemiconductor device 10A is externally dissipated via the arm 105 andthe casing 101. Since in this example, an application to a hard disk isassumed, a flexible sheet 109 has been selected for the use as the firstsupporting member 11, however, depending on the types of the apparatus,a printed board or a ceramic substrate etc. may instead be selected asthe first supporting member 11.

Also, herein, Au or a brazing material such as solder is applied to theback surface of the semiconductor chip 16 in order to affix a metalplate 23 to the back surface of the semiconductor chip 16.

Embodiment 2

The semiconductor device according to the second embodiment of thepresent invention will now be explained with reference to FIGS. 2A and2B. FIG. 2A is a plan view of the semiconductor device, and FIG. 2B is across-sectional view taken along the ling A—A.

In FIG. 2A, the following elements are shown as embedded within aninsulating resin 13; bonding metal members 14 and a semiconductor chip16 disposed over the region surrounded by the bonding metal members 14.As apparent from the manufacturing step shown in FIG. 7, thesemiconductor chip 16 is affixed within an isolation trench 22 via abrazing material or a conductive paste etc. It may alternatively beaffixed by an insulating adhesive means.

The bonding electrodes 19 of the semiconductor chip 16 and the bondingmetal members 14 are electrically connected via thin metal lines 20.

The back surfaces of the bonding metal members 14 are exposed from theinsulating resin 13, and as they are, form external connectionelectrodes 21, and the side surfaces of the bonding metal members 14 areetched non-anisotropically. These etched portions are formed by a wetetching method, so that they have a curved structure which promotes ananchor effect.

This structure is formed by three elements including the semiconductorchip 16, a plurality of metal members 14, the insulating resin 13 withinwhich the former two are embedded. Within a region for disposing thesemiconductor chip 16, the back surface of the semiconductor device 10Ais exposed. All the elements including the above are sealed within theinsulating resin 13. The bonding metal members 14 and the semiconductorchip 16 are supported by this insulating resin 13.

As for the insulating resin 13, a heat-curable resin such as epoxyresin, or a thermoplastic resin such as polyimide resin or polyphenylenesulfide etc. may be used.

Any resin material can be used as the insulating resin as long as it canbe cured within a metal mold, or can be applied by dipping or coating.For the metal member 14, a conductive foil mainly made of Cu, aconductive foil mainly made of Al or an Fe—Ni alloy, a laminate of Al—Cuor a laminate of Al—Cu—Al or the like may be used. Of course otherconductive material may also be used, and especially desirable are thoseconductive materials that can be etched, or that can be evaporated bylaser. When the half-etching, plating and thermal stress characteristicsare concerned, a conductive material mainly made of Cu formed throughrolling is suitable.

According to the present invention, the trench 22 is also filled withthe insulating resin 13 so that slipping-out of the metal member 14 maybe prevented. Also, by performing non-anisotropic etching through adry-etch or wet-etch method, the side surfaces of the bonding metalmembers 14 may be processed to have a curved structure thereby promotingthe anchor effect, which in turn realizes a structure that would notallow the metal member 14 to slip out from the insulating resin 13.

Moreover, the back surface of the semiconductor chip 16 is exposed fromthe back surface of the package. Therefore, the back surface of thesemiconductor chip 16 would form a structure that can be abutted orattached to the later-described metal plate 23, the second supportingmember 24 or a fixation plate 25 formed on the second supporting member24. Accordingly, this structure allows the heat generated by thesemiconductor chip 16 to be dissipated into the second supporting member24, thereby preventing the temperature rise of the semiconductor chip 16so that the driving current and driving frequency of the semiconductorchip 16 may be increased.

In the semiconductor device 10A, since the metal member 14 is supportedby the insulating resin 13, which is a sealant, the use of anysupporting substrate is made unnecessary. This structure is one featureof the present invention. The conductive paths of the conventional artsemiconductor device are supported by a supporting substrate (flexiblesheet, printed board or ceramic substrate), or by a lead frame, and thismeans that the conventional art device includes those elements thatcould potentially be made unnecessary. On the other hand, the device ofthe present invention is constituted by only essential, minimalelements, and it eliminates the need for a supporting substrate, thus itcan be made thin and light-weighted, and at the same time, its cost maybe reduced as it requires less material cost.

On the back surface of the package (semiconductor device 10A), aninsulating film 26 is formed in order to allow a film of the brazingmaterial to be provided in a uniform thickness. The regions surroundedby dotted lines 27 shown in FIG. 2A indicate the portions of thesemiconductor chip 16 exposed from the insulating film 26, and theseportions are exposed in the same manner as the exposed square-shapedportions of the back surfaces of the bonding metal members 14, theindividual potions of the semiconductor chip 16 exposed from theinsulating film 26 and the exposed portions of the bonding metal members14 have the same size.

Thus, the sizes of the portions wettable by the brazing material aresubstantially identical so that the brazing material formed theretowould have substantially the same thickness. This would not change evenafter a solder print or reflow process.

The same is true for a conductive paste of i.e. Ag, Au or Ag—Pd etc.Given this structure, more accurate calculation can be performed todetermine how much the back surface of the metal plate should protrudebeyond the back surfaces of the bonding metal members 14. Where solderballs are formed as shown in FIG. 2B, the bottom ends of the solderballs may be abutted to conductive paths of the mounting board, so thatsoldering failure may be eliminated.

The exposed portions 27 of the back surface of the semiconductor chip 16may be formed to have a larger size than that of the exposed portions ofthe bonding metal member in consideration with the dissipationcapability of the heat from the semiconductor chip.

The provision of the insulating film 26 also allows the conductivepattern 32 provided on the first supporting member 11 to be disposedover the back surface of the semiconductor device. Generally, theconductive pattern 32 provided in the first supporting member 11 is soarranged that it bypasses the region in which the semiconductor deviceis attached, however, the provision of the insulating film 26 allows itto be disposed without such bypassing. In addition, since the insulatingresin 13 protrudes beyond the conductive pattern, a gap may be formedbetween the wirings on the first supporting member 11 and the conductivepattern, thereby enabling to prevent short-circuiting.

Embodiment 3

FIGS. 3A and 3B show another semiconductor device 10B according to thepresent invention. FIG. 3A is a plan view thereof, and FIG. 3B is across-sectional view taken along the line A—A. Since this structure issimilar to that of FIGS. 2A and 2B, the following provides only thedescription pertinent to those features that are different from thedevice in FIGS. 2A and 2B.

In FIG. 2B, the back surfaces of the bonding metal members 14 are usedas the external connection electrodes as they are, however, in thisembodiment, a wiring 30 and an external connection electrode 31integrally formed with the wiring 30 are provided to each of the bondingmetal members 14.

The rectangle shown by a dotted line represents the semiconductor chip16, and on the back surface of the semiconductor chip 10B, the externalconnection electrodes 31 are disposed in a ring-like arrangement asshown, or in a matrix. This arrangement is identical or similar to thatof known BGA. The wirings 30 may be formed in a wavy shape with respectto the distortion at the bonding portion.

The locations at which the device is connected with the conductivepattern 32 of the first supporting member 11 would be the externalconnection electrodes 31, and the back surfaces of the bonding metalmembers 14 and the lines 30 are covered by the insulating film 26. Thedotted circles indicated in the regions of the external connectionelectrodes 31 and the semiconductor chip 16 represent the portions thatexpose from the insulating film 26.

Furthermore, since the semiconductor chip 16 is provided within theinner side of the external connection electrodes 31, this semiconductorchip is designed to be smaller than the semiconductor chip shown inFIGS. 2A and 2B. Accordingly, the insulating resin 13 covers the bondingmetal members 14 and wirings 30, the semiconductor chip 16 and the metalthin lines 20.

The present embodiment has an advantage in that, even when the number ofthe bonding metal members 14 is extremely large and their size has to bereduced, the size of the external connection electrodes 31 may be madesufficiently large by connecting them via the wirings and rearrangingthem as the external connection electrodes. The presence of the wiringsalso alleviates the distortion stress applied to the connections of themetal thin lines and the connections of solder.

According to this embodiment, the back surface of the semiconductor chip16 is entirely exposed as shown in FIGS. 3A and 3B, however, the backsurface of the semiconductor chip 16 can be covered with the insulatingfilm 26 and exposed from the insulating film 26 at the (square-shaped orcircle-shaped) exposed portions as described in the second embodimentand shown in FIGS. 2A and 2B.

Embodiment 4

The fourth embodiment explains a manufacturing method of thesemiconductor devices 10A and 10B. Herein, the semiconductor device 10Bin FIG. 3B is used to illustrate the manufacturing method. FIGS. 4through 8 are the cross-sectional views of FIG. 3A taken along the lineA—A.

First, as shown in FIG. 4, a conductive toil is provided. The thicknessof the foil is desirably between 10 μm and 300 μm, and herein, a rolledcopper foil in a thickness of 70 μm is used. Next, over the surface ofthis conductive foil 40, a conductive film 41 or a photo resist isformed as an etching mask. This pattern is identical to the patterns ofthe bonding metal members 14, wirings 30 and external connectionelectrodes 31 of FIG. 3A. Where a photo resist is used instead of theconductive film 41, a conductive film of Au, Ag, Pd, Ni or the likeshould be provided under the photo resist at least over the portionscorresponding to the bonding metal members. This film is provided toenable the bonding. (FIG. 4).

Thereafter, the conductive foil 40 is half-etched via the conductivefilm 41 or the photo resist. The depth of etching may be arbitrary solong as that it is shallower than the thickness of the conductive foil40. A shallower etching depth allows the formation of a finer pattern.

By this half-etching, convex metal members of 14, 30 and 31 manifest onthe surface of the conductive foil 40. The conductive foil 40 usedherein is a Cu foil mainly made of Cu, which has been formed by rollingas priorly mentioned. However, it may also be a conductive foil made ofAl or an Fe—Ni alloy, or a laminate of Cu—Al or Al—Cu—Al. The laminateof Al—Cu—Al, especially, can prevent warping caused by a difference inthermal expansion coefficients.

An adhesive means 17 is then provided on the bottom of the isolationtrench 22 which has been formed in the region surrounded by the externalconnection electrodes 31. The attachment of the semiconductor chip maybe achieved via the conductive foil, the brazing material and theconductive paste, by forming a conductive film such as the one made ofAu etc. over the back surface of the semiconductor chip. In this case, abrazing material such as solder etc. or bumps may be formed as shown inFIG. 3B. However, where this attachment is obtained through aninsulating adhesive, then the formation of the brazing material such assolder etc. or bumps would be more difficult. (FIG. 5).

The semiconductor chip 16 is then affixed to the region in which theadhesive means 17 has been provided, and the bonding electrodes 19 ofthe semiconductor chip 16 and the bonding metal members 14 areelectrically connected. In the embodiment shown in the diagrams, sincethe semiconductor chip 16 is mounted with its face up, the metal thinlines 20 are used as the connecting means.

In this bonding process, since the bonding metal members 14 are integralwith the conductive foil 40, and the back surface of the conductive foil40 is flat, it can be abutted to the table of the bonding machine by theplane. Accordingly, if the conductive foil 40 is perfectly fixed to thebonding table, misalignment of the bonding metal members 14 would notoccur, thus the bonding energy can be efficiently transmitted to themetal thin lines 20 and the bonding metal members 14. This allows theconnections of the metal thin lines 20 to have improved attachmentstrength. The fixation to the bonding table may be achieved by, forexample, providing a plurality of vacuum holes over the entire surfaceof the table. Alternatively, the conductive foil 40 may be pressed fromthe above.

The semiconductor chip may be mounted without using a supportingsubstrate, and it may be affixed onto the bottom of the isolation trench22, therefore the semiconductor chip 16 may be disposed at a positionlower by that extent. Accordingly, the outer thickness of the packagemay be reduced as later explained. (FIG. 6).

The insulating resin 13 is then formed so as to cover the bonding metalmembers 14, the wirings 30, and the external connection electrodes 31formed via the half-etching, and the semiconductor chip 16 and the metalthin lines 20. For the insulating resin, either a thermoplastic resin ora heat-curable resin may be used.

It may be formed via transfer molding, injection molding, dipping orcoating. For a heat-curable resin such as epoxy resin, transfer moldingmay be employed, and for a thermoplastic resin such as liquid crystalpolymer or polyphenylene sulfide etc., injection molding may beemployed.

In the present embodiment, the thickness of the insulating resin isadjusted so that its top end comes at approximately 100 μm from the topportions of the metal thin lines 20. This thickness may be made largeror smaller depending on the desired strength of the semiconductordevice.

Since the bonding metal members 14, wirings 30 and the externalconnection electrodes 31 are all integral with the conductive foil 40that is in a form of a sheet, these copper foil patterns would never bedisplaced during the resin injection step as long as the conductive foil40 itself is not displaced.

As explained in the above, within the insulating resin 13, the bondingmetal members 14, wirings 30 and external connection electrodes 31 thatare formed to be convex features are embedded along with thesemiconductor chip 16, and the portion of the conductive foil 40 belowits convex features is exposed from the back surface. (FIG. 7).

Thereafter, the portion of the conductive foil 40 exposed on the backsurface of the insulating resin 13 is eliminated, thereby separating thebonding metal members 14, wirings 30 and external electrodes 31 intoindividual elements.

For this separation step, various approaches may be contemplated. Forexample, they may be separated by etching the back surface, or bypolishing or grinding, or even by the combination thereof. For example,where the grinding is performed until the insulating resin 13 isexposed, there is a risk of having residues or stretched metal particlesfrom the ground conductive foil 40 encroach into the insulating resin13. Accordingly, by using an etching approach, the separation may beachieved without having the metal residues from the conductive foil 40encroach into the surface of the insulating resin 13 located between theCu patterns. In this way, short-circuiting between the patterns that arearranged at fine intervals may be prevented.

In a case where a plurality of units, each comprising a singlesemiconductor device 10B, are integrally formed, a dicing step isadditionally performed after this separation step.

Although a dicing apparatus is used herein to individually separate theunits, it is also possible to perform this step bychocolate-bar-breaking, pressing or cutting.

According to this embodiment, after separating the Cu patterns, aninsulating film 26 is formed over the patterns for 14, 30 and 31 thatare isolated and exposed from the back surface, and the insulating film26 is then patterned so as to expose the portions indicated by thedotted circles shown in FIG. 3A. Thereafter, it is diced at the sectionsindicated by arrows into individual semiconductor devices 10B.

The solder balls 42 may be formed either before or after the dicingstep.

According to the manufacturing method above, a thin and small package isfabricated, in which the bonding metal members, wirings, externalconnection electrodes and a semiconductor chip are embedded within theinsulating resin.

The effects obtained by the above manufacturing method will now beexplained in the following section.

First, since the metal members are half-etched and supported integrallywith the conductive foil, a substrate that has been conventionallyemployed for supporting is made unnecessary.

Second, since the convex metal members are formed by half-etching theconductive foil, it is possible to form finer metal members.Accordingly, their widths and intervals may be minimized, allowing theformation of a package having a smaller two-dimensional size.

Third, since the device may be constituted by metal members, asemiconductor chip, connection means and a sealing material, thestructure would include only the elements that are truly essential,eliminating the excessive use of materials, thus, a thin and smallsemiconductor device may be realized with a substantially reduced cost.

Fourth, since the bonding metal members, wirings and external connectionelectrodes are formed as convex portions through half-etching, and theseparation to individual elements is performed after the sealing step,tie-bars and suspension leads would not be necessary. Accordingly, thenecessity for the formation of tie-bars (suspension leads), and cuttingstep of the tie-bars (suspension leads) are completely eliminated in thepresent invention.

Fifth, since the conductive foil is eliminated from the back surface ofthe insulating resin to separate the metal members after the convexmetal members are embedded within the insulating resin, flashes of theresin formed between leads as those present in the conventional leadframes can be eliminated.

Sixth, since the semiconductor chip is exposed from the back surface,the heat generated by the semiconductor device can be dissipatedefficiently from the back surface of the semiconductor device.

Embodiment 5

The fifth embodiment is provided for illustrating a semiconductor device10A, 10B to which a metal plate 23 is affixed and a semiconductor moduleusing the same. FIG. 1A shows this type of semiconductor module (FCA)50. The semiconductor device mounted thereto is the semiconductor device10A shown in FIGS. 2A and 2B.

First, a first supporting member 11 constituted by a flexible sheet willbe explained. In the present embodiment, it comprises a first PI sheet51, a first adhesion layer 52, a conductive pattern 53, a secondadhesion layer 54 and a second PI sheet 55 that are sequentiallylaminated from the bottom. When forming the conductive pattern inmultiple layers, additional adhesion layers may be used, and upper andlower layers of the conductive pattern may be electrically connectedthrough contact holes. Provided in this first supporting member 11 is afirst opening 12 which would allow at least a metal plate 23 to beexposed as shown in FIG. 1C.

A second opening 56 is also formed in order to expose the conductivepattern. The second opening 56 may entirely expose the correspondingconductive pattern 32, or may partially expose only the portion forforming connections. For example, the second PI sheet 55 and the secondadhesion layer 54 may entirely be eliminated, or, as shown in thefigure, while entirely eliminating the second PI sheet 55, the secondadhesion layer 54 may partially be eliminated only at the locationsrequired to be exposed. According to the later manner, running of thesolder 27 may be prevented.

In the semiconductor device of the present invention, a metal plate 23is adhered to the back surface of the semiconductor chip 16. In thesemiconductor module of the present invention, the back surface of thefirst supporting member and the metal plate 23 would becomesubstantially within a same plane.

The thickness of the metal plate 23 is determined according to thethicknesses of the first supporting member 11 and the fixation plate 25.The thicknesses of the respective elements are determined in a manner sothat the metal plate 23 exposed from the first opening 12 can besubstantially within a same plane with the back surface of the firstsupporting member 11 when the bonding metal members 14 and theconductive pattern 32 are affixed together through the solder balls 27.Accordingly, the metal plate 23 may be abutted to the second supportingmember or abutted and adhered to the fixation plate 25 provided on thesecond supporting member.

Several examples of this connection structure are given below.

In the first example of the structure, a light-weight metal plate suchas the one made of Al or stainless steel etc., or a ceramic substrate isused as the second supporting member 24, and the metal plate 23 whichhas been affixed on the back surface of the semiconductor device 10A isabutted thereto. That is, in this structure, the abutment to the secondsupporting member 24 is provided without the use of the fixation plate25. The fixation between the semiconductor chip 16 and the metal plate23, and between the metal plate 23 and the second supporting member 24is achieved by a brazing material such as solder etc. or an insulatingadhesive means containing fillers having a good thermal conductivity.

In the second example, the structure employs a light-weight metal platesuch as the one made of Al or stainless steel etc. or a ceramicsubstrate as for the second supporting member 24, and a fixation plate25 is formed thereon, and this fixation plate 25 and the metal plate 23are affixed together.

Where an Al plate is used as the second supporting member 24 forexample, the fixation plate 25 is preferably the one made of Cu. This isbecause Cu can be plated over Al to form a Cu film in a thickness up toabout 10 μm. In addition, since it is a plated film, it may be formed inintimate contact with the second supporting member 24, making thethermal resistance between the fixation plate 25 and the secondsupporting member 24 extremely small.

Alternatively, the Cu fixation plate 25 and the Al substrate may beadhered using an adhesive, however, in this case the thermal resistancewould become larger.

Where a ceramic substrate is used as the second supporting member 24,the fixation plate 25 is attached on an electrode formed by print-bakinga conductive paste.

The second supporting member 24 and the first supporting member 11 areadhered together via a third adhesion layer 57.

For instance;

-   First PI sheet 51: 25 μm-   Second PI sheet 55: 25 μm-   First and second adhesion layers 52 and 54: 25 μm after being baked    (an acrylic adhesive is used)-   Solders 27: 50 μm;-   Third adhesion layer 57: 25 μm (an acrylic adhesive is used);    Where the thicknesses of the respective layers are adjusted and    determined in this way, even if the second supporting member 24    having the fixation plate 25 formed thereon is adhered onto the    first supporting member 11 after affixing the semiconductor device    10A to the first supporting member 11, the metal plate may be    abutted to the fixation plate, so that the connection failure would    not occur.

Where a module is provided, in which the second supporting member 24 isattached to the first supporting member 11, and the semiconductor device10 is placed within an opening 56 provided in this module and thensoldered, the soldering may be performed at once without promotingconnection failures.

Accordingly, the heat generated by the semiconductor chip 16 may bedissipated into the second supporting member 24 via the metal plate 23and the fixation plate 25. Moreover, since it provides a substantialreduction in the thermal resistance compared to that of the conventionalart structure (FIG. 15B), the driving current and the driving frequencyof the semiconductor chip 16 can be maximized. The back surface of thissecond supporting member 24 may be attached to the actuator 107, bottomof the casing 101 or the arm 105 shown in FIG. 14. Therefore, the heatfrom the semiconductor chip can ultimately be emitted to the outside viathe casing 101. Accordingly, even if the semiconductor module is mountedin the hard disk 100, the temperature of the semiconductor chip itselfis kept relatively low, so that the read/write speed of the hard disk100 can be further accelerated. This FCA may be mounted on an apparatusother than a hard disk. In this case, the second supporting membershould be abutted to a member of the apparatus having a small thermalresistance.

Embodiment 6

The sixth embodiment is provided to illustrate a semiconductor device10C in which the metal plate 23 and the bonding metal members are formedfrom a same material, and a semiconductor module 50A using the same.First, the manufacturing method thereof will be explained with referenceto FIGS. 10 and 11. Its manufacturing steps corresponding to the stepsillustrated in FIGS. 4 through 7 are identical and the descriptions forthese steps would not be repeated.

FIG. 10 is showing the conductive foil 40 being covered by theinsulating resin 13, and on the portion corresponding to the metal plate23, a photo resist PR is formed. When this conductive foil 40 is etchedvia the photoresist PR, the resultant metal plate 23 would have astructure which protrudes beyond the back surfaces of the bonding metalmembers 14. Alternatively, a conductive film made of Ag or Au etc. maybe selectively formed and used as a mask instead of the photo resist PR.This film would function also as an anti-oxidizing film.

In the structure such as the one shown in FIG. 1B in which the metalplate 23 is adhered, since the metal plate 23 is extremely thin (i.e.125 μm), the workability is extremely poor. On the other hand, where themetal plate 23 is formed through etching as the protrusive structure,the attaching step of the metal plate 23 may be eliminated.

Next, as shown in FIG. 12, after the bonding metal members 14, wirings30 and external connection electrodes 31 are completely separated, theinsulating film 26 is formed, and the portions for forming solder balls21 are exposed. After the solder balls 21 are provided, it is diced atthe sections indicated by arrows.

The isolated semiconductor device is then mounted on the firstsupporting member 11 as shown in FIG. 9. Thereafter, the secondsupporting member 24 is attached thereto as previously mentioned. Atthis point, since the metal plate 23 is protrusive, it can be readilyconnected to the fixation plate 25 via soldering etc.

Embodiment 7

The seventh embodiment is provided to illustrate another semiconductordevice. FIG. 13A shows a plan view of the semiconductor device accordingto the present invention, and FIG. 13B shows a cross-sectional view ofFIG. 13A taken along the line A—A.

According to the present embodiment, semiconductor chips 16A and 16B arepackaged, and at the peripheries of these semiconductor chips, bondingmetal members 14 are provided. The back surfaces of these bonding metalmembers themselves serve as the external connection electrodes, however,the re-arranged type of wirings shown in FIGS. 3A and 3B may instead beemployed. Between the first and second semiconductor chips 16A and 16B,at least one bridge 71 is disposed.

The first semiconductor chip 16A and the second semiconductor chip 16Bare connected via metal thin lines 20.

The metal thin lines include a first set of metal thin lines 20A thatare connected to the bonding metal members 14 and a second set of metalthin lines 20B that are connected to the bridges 71. A plurality ofbonding electrodes 19 are provided on the semiconductor chips. Accordingto I/O signals to and from the bonding electrodes 19, at least a part ofthe bonding electrode 19 are selected, and the locations and count ofthe bonding metal members 14 are determined correspondingly. Theselected bonding electrodes 19 on the semiconductor chips and thebonding metal members 14 are connected via the first set of metal thinlines 20A.

On the other hand, the connection between the first and secondsemiconductor chips 16A and 16B is provided by the second set of metalthin lines 20B connecting between the bonding electrodes 19 on the firstsemiconductor chip 16A and one ends of the bridges 71, and between theother ends of the bridges 71 and the bonding electrodes 19 on the secondsemiconductor chip 16B.

Since the bridges 71 are provided in the present structure, the ends ofthe metal thin lines connected on the side of the first and secondsemiconductor chips 16A and 16B may all be connected by ball bonding.

As apparent from the manufacturing method previously explained, byhalf-etching the conductive foil, and performing the molding of theinsulating resin 13 before it is completely isolated, the risk of havingthe bridges 71 fall down or slip out may be eliminated.

According to the present invention, a plurality of chips may be packagedinto a single package as this embodiment.

The embodiments described heretofore are provided in order to illustratethe structures designed in consideration with the heat-dissipatingcapability of a single read/write amplifying IC. However, where theapplications to various types of apparatus are contemplated, there maybe a case in which the heat-dissipating capability of a plurality ofsemiconductor chips must be considered. Of course, it is possible topackage them into separate, individual packages, however, the pluralityof the semiconductor chips may also be packaged into one package asillustrated in FIGS. 13A and 13B.

The metal plates may of course be connected to the semiconductor chipsas shown in FIG. 1B, and these may be mounted on a flexible sheet or aflexible sheet having the second supporting member attached thereon.

The embodiments described above are explained with a flexible sheet as asubstrate, however, a ceramic substrate, a printed board, a flexiblesheet, a metal substrate or a glass substrate etc. can also be appliedto the substrate of the present invention.

As apparent from the above description, according to the presentinvention, a metal plate is affixed to a semiconductor chip exposed fromthe back surface of a package to provide a semiconductor device in whichthe metal plate protrudes beyond the back surfaces of externalconnection electrodes or the bonding metal members, thereby facilitatingthe mounting of the device on an FCA.

Especially, by providing an opening to the FCA so as to allow the backsurface of the FCA to be within a same plane with the back surface ofthe semiconductor chip, the abutment to the second supporting member canbe readily achieved.

By using Al as for the second supporting member material and by formingthereon a fixation plate made of Cu, and affixing the metal plate tothis fixation plate, the heat generated by the semiconductor chip may beexternally dissipated via the second supporting member.

Accordingly, the temperature rise of the semiconductor chip may beprevented, allowing the device to operate at a higher performance levelclose to its inherent capability. Especially, such an FCA used in a harddisk is capable of providing efficient external emission of heat so thatthe read/write speed of the hard disk may be increased.

1. A semiconductor module comprising: a semiconductor device including:a semiconductor chip integrally sealed in an insulating resin but havinga back surface exposed and free from the insulating resin; a metalmember sealed in the insulating resin with the semiconductor chip, themetal member having a top surface on which a pad is electricallyconnected to a bonding electrode of the semiconductor chip, sidesurfaces that are curved, and a back surface that is exposed and freefrom the insulating resin; a first supporting member having a conductivepattern provided therein, said conductive pattern being partiallyexposed to connect electrically to the exposed back surface of the metalmember, and said first supporting member having an opening at a locationcorresponding to the semiconductor chip; a metal plate provided on theback surface of the semiconductor chip in the opening; and a secondsupporting member having the metal plate affixed thereto is adhered ontothe back surface of the first supporting member; wherein a fixationplate made of a conductive material is provided on the second supportingmember at a location corresponding to the metal plate, the fixationplate and the metal plate thermally coupled, and the metal plate ismainly made of Cu, the second supporting member is mainly made of Al,and the fixation plate is constituted by a plated film mainly made of Cuformed on the second supporting member.
 2. A semiconductor module asclaimed in claim 1 wherein the back surface of the insulating resinprotrudes beyond the back surface of the metal member.
 3. Asemiconductor module as claimed in claim 1, wherein the semiconductorchip is a read/write amplifying IC for a hard disk.
 4. A semiconductormodule comprising: a semiconductor device including: a semiconductorchip integrally sealed in an insulating resin but exposed and free fromthe insulating resin at a semiconductor chip's back surface; an externalconnection electrode integrally sealed in the insulating resin with thesemiconductor chip, said external connection electrode having a topsurface on which a pad is electrically connected to a bonding electrodeof the semiconductor chip and on which a wiring extends from the pad,side surfaces that are curved, and a back surface that is exposed andfree from the insulating resin; a first supporting member having aconductive pattern provided therein, said conductive pattern beingpartially exposed to couple electrically to the exposed back surface ofthe external connection electrode, said first supporting member havingan opening at a location corresponding to the semiconductor chip; ametal plate affixed to the semiconductor chip through the opening; and asecond supporting member having the metal plate affixed thereto andadhered onto the back surface of the first supporting member; wherein afixation plate made of a conductive material is provided on the secondsupporting member at a location corresponding to the metal plate, thefixation plate and the metal plate thermally coupled and the metal plateis mainly made of Cu, the second supporting member is mainly made of Al,and the fixation plate is constituted by a plated film mainly made of Cuformed on the second supporting member.
 5. A semiconductor module asclaimed in claim 4, wherein the external connection electrode and themetal plate are integrally formed from a same material.
 6. Asemiconductor module as claimed in claim 4, wherein the back surface ofthe insulating resin protrudes beyond the back surface of the externalconnection electrode.
 7. A semiconductor module as claimed in claim 4,wherein the semiconductor chip is a read/write amplifying IC for a harddisk.